Some wonderful ideas here.
I keep a large plastic tub in the freezer in my refrigerator. After every meal if there is veggie/meat broth left in a dish or a tiny portion of meat or veggies left that isn't enough for another meal or to pack in my lunch it gets scooped into the tub. When it's full I thaw it check the ingredients and make veggie soup. Sometimes I have to add some onion or celery and a wee bit of seasoning. Usually it's fine as is. It's like getting a meal for f-r-e-e. Put anything in there that you would normally add to soup. Free meal, nothing goes bad in the back of the fridge.